Inflammation Flashcards
What is inflammation?
Natural response of the body to a pathogen or injury
First step in the healing process
Aims to attract leukocytes in the affected area
Mainly a function of the blood vessels
Which are the cardinal signs of inflammation and why do they occur?
Pain - chemical mediators and stretching from swelling stimulate sensory nerve endings
Swelling - increased vascular permeability causes oedema
Redness - increased blood flow due to vascular dilation
Warmth - “”
Loss of function - due to pain and swelling
What is a pathogen?
Any organism that causes disease in another organism
Describe the chain of infection
infectious agent reservoir portal of exit modes of transmission portals of entry susceptible host
What are the functional characteristics of leukocytes?
Diapedesis - ability to slip out of capillaries and into the tissues
Amoeboid motion - moving through tissue spaces by forming cytoplasmic extensions and rolling along other cells
Positive chemotaxis - ability to pinpoint affected areas by following chemical trails of inflammatory molecules
Describe the basic inflammatory process
Pathogens enter wound
Platelets release blood clotting proteins
Mast cells secrete factors that cause vasodilation and increased delivery of blood, plasma and cells
Neutrophils secrete factors that kill and degrade pathogens
Neutrophils and macrophages remove pathogens by phagocytosis
Macrophages secrete cytokines that attract immune system cells and activate cells involved in tissue repair
Response continues until foreign material is eliminated
Describe the control of inflammation
Pro-inflammatory cytokines - TNF-a activate IKK complex which liberates NF-KB and translocates into the nucleus
Activate JNK-AP-1 pathway
Coordinated actions of NF-KB and AP-1 propagate inflammation - promote transcription of proinflammatory genes
Describe the role of NF-KB
It is a transcription factor that controls the rate of transcription of genetic information from DNA to mRNA by binding to a specific DNA sequence
Maintains inflammation
Activated by cytokines (TNF-a) and secretes cytokines (TNF-a)
What are the 4 resolutions of inflammation?
healing
abscess formation
fibrosis
chronic inflammation
What are the main characteristics of inflammation?
The chronic presence of lymphocytes and macrophages in the affected tissue
Neo-vascularisation
Fibrosis and necrosis of tissues in and around the affected area
Active inflammation, tissue damage and healing process occur at the same time
What are the potential causes of chronic inflammation?
Persistent infections - delayed hypersensitivity
Prolonged exposure to toxic agents - smoking
Autoimmunity
Does exercise influence inflammation?
Cytokines are elevated after an exercise bout
This triggers an anti-inflammatory cascade when exercise stops
Main cytokine triggered is IL-6 (release CRP) which increases during exercise then drops dramatically when exercise stops - IL-6 increases as a direct response to a decrease in muscle glycogen content
When exercise stops there is an increase in IL-1ra (anti-inflammatory cytokine) which stops the receptor of IL-1
What happens with Chronic exercise and inflammation?
Elderly that actually exercise have comparable markers to the young - if someone exercises that inflammatory markers are fairly low
How does PGC1a affect the inflammatory process?
It is released by the contracting muscle (involved in adaptations for endurance exercise). When conc is increased it blocks the function of NK-KB - a key driver in the inflammatory process. NF-KB has role in muscle atrophy therefore PGC1a inhibits fibre atrophy
